Our IBM xSeries 255 ServerRaid 4MX Ultra Controller seems to have gone bad and we are attempting to replace it with the Single Channel Controller Card 4LX question is will we lose all the data stored across the raid when the 4LX Controller is configured during setup.

This is not the best place to ask for help on corporate RAID problems.

I suggest going to IBM for support on your problem. The obvious thing here is you need determine the RAID settings... You have to ask yourself , "Does the new card offer the same options as the old/defective one?". Also, in a corporate environment, I hope you had backups.

The data will remain on the discs (not sure what RAID you were using, and assuming the bad RAID card did not corrupt the data), the bottom line is you need to match the configuration. The forums at 2cpu.com may be a better place for you.